JPH0665028B2 - Method for manufacturing battery electrode - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a battery electrode suitable for a power source of various electric appliances oriented toward miniaturization and thinning.

<Prior art and its problems> For electrodes of conventional batteries for electronic devices, a conductive material and a binder are added to an electrode active material, and the mixture is kneaded well, and the kneaded product is applied to a collector such as a metal net. It can be obtained by wearing and molding. It is widely used to mount this electrode on a counter electrode via a separator to form a battery structure.

However, the electrode manufactured by such a method has a drawback in that the electrical contact between the electrode active material, the conductive material and the current collector is poor, and the electrode has a large resistance component. Further, since it is necessary to add a conductive material and a binder in addition to the electrode active material, the amount of the electrode active material is limited, which causes a decrease in energy density. Further, it is necessary to perform a charging operation in which the obtained active material of the electrode is introduced by an electrochemical operation in an electrolytic solution in advance before forming a battery, which is one cause of complication of the manufacturing process.

The present invention has been made in view of the above circumstances, and an object of the present invention is to bring about a reduction in battery capacity based on poor electrical contact between an electrode active material, a conductive agent, and a current collector, and, in particular, and It is possible to increase the energy density without using a binder, etc. Moreover, it can be applied as a battery electrode without performing a charging operation before the battery is constructed, and the manufacturing process can be simplified and manufactured at low cost. Is to provide a method.

<Means for Solving Problems> In the method for producing a battery electrode according to the present invention, a carbonaceous material is directly deposited on a conductive substrate having a three-dimensional structure by a vapor deposition method by low temperature pyrolysis of hydrocarbons. Then, the three-dimensional structure is filled with a charge carrier substance capable of reversibly intercalating and deintercalating with the carbonaceous material directly deposited on the conductive substrate, and then the charge carrier is filled. It is characterized in that the three-dimensional structure filled with the substance is compressed to form an electrode body.

In the battery electrode manufacturing method according to the present invention, the conductive substrate having a three-dimensional structure may be in any form such as foam (sponge), wool, woven fabric, non-woven fabric, and net. It may be at least a plastic having a plasticity capable of being changed in shape by being compressed by a pressure applied from the outside and having conductivity, or a surface of which is coated with a material having conductivity. .

The carbonaceous material used in the present invention can be deposited on a suitable substrate by a vapor deposition method by low temperature pyrolysis of hydrocarbons. At this time, the starting hydrocarbons may be any of aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons and the like. In addition, these may contain various heteroatoms such as nitrogen atom and oxygen atom, and have a characteristic group such as a halogen atom, a hydroxyl group, a sulfonic acid group, a nitro group, a nitroso group, an amino group, an azo group and a carboxyl group. It may be added or substituted. Hydrocarbons that are pyrolyzed at low temperature are vaporized, fed to the reaction system, and pyrolyzed in the reaction system. The concentration of the hydrocarbons to be pyrolyzed and the temperature to be pyrolyzed differ depending on the hydrocarbons used as the starting material, but usually a concentration of several millimole percent and 1000 ° C.
A temperature below about the above is suitable. As a method of vaporizing hydrocarbons as a starting material, there are a bubbler method using argon gas as a carrier gas, a bubbler method using various carrier gases, an evaporation method, a sublimation method, and the like.

An electrode obtained by depositing a carbonaceous material on a conductive substrate having a three-dimensional structure carries a charge carrier substance capable of reversibly intercalating and deintercalating with the carbonaceous material, It is compressed and molded by the applied pressure. Here, as the charge carrier substance, a powder of a donor type substance such as an alkali metal, an alkaline earth metal or a rare earth metal, and an acceptor type substance such as a halogen, a halogen compound, a metal oxide, an oxygen acid or a hydride. Shapes, flakes, liquids, sols, gels and the like can be used. Although it is practically preferable to carry out the compression by roller rolling, it may be carried out by a press molding machine or other pressing means. The electrode can be arbitrarily controlled up to the compression limit of the three-dimensional structure by compression, and a molded product having an intended thickness within this range can be appropriately obtained.

In this way, the electrode that can be obtained by the manufacturing method of the present invention is a non-aqueous electrolyte battery using a non-aqueous electrolyte solution as an electrolytic solution, a non-aqueous solid electrolyte battery using a non-aqueous solid electrolyte, and an aqueous solution as an electrolytic solution. It can be used as an electrode for various batteries such as alkaline batteries, acid batteries, fuel cells, and solid electrolyte batteries.

<Operation> According to the present invention, an electrode obtained by directly depositing a carbonaceous material from a vapor phase on a conductive substrate material having a three-dimensional structure by low-temperature pyrolysis of hydrocarbons is reversible with the carbonaceous material. It is possible to obtain a battery electrode by carrying a charge carrier substance which can be intercalated and deintercalated, and formed by compression of these three-dimensional structures.

Since the carbonaceous material that is the electrode active material is directly deposited on the conductive substrate that is the charge collector, and electrically and mechanically connected,
No binding agent or conductive agent is required, and high capacity is possible.
Furthermore, since the charge carrier material is supported on the carbonaceous material,
There is no need to perform electrode chemical conversion treatment prior to battery construction.

This is because the carbonaceous material is in contact with the electrode carrier substance, so that a reaction occurs when a battery is manufactured (when it is in contact with the electrode liquid) to form an intercalation compound.

<Effects of the Invention> The electrode obtained by the production method of the present invention has a high capacity density and does not deteriorate due to repeated charging / discharging over a long period of time. Therefore, by constructing a battery using the electrode, the energy density can be improved. It is possible to obtain a battery having a high cycle life and an excellent cycle life. Furthermore, in the electrode manufacturing process,
Since the complicated steps such as kneading, coating, drying and charging of the active material can be omitted, the steps can be simplified and facilitated. That is, since the manufacturing method of the present invention can provide an electrode having a high capacity density and an excellent cycle life, and can simplify and shorten the manufacturing process, the manufacturing method of the present invention has excellent characteristics. Moreover, an inexpensive electrode can be obtained, and its industrial value is extremely large.

<Examples> The present invention will be described in more detail with reference to Examples. still,
The present invention is not limited to the following examples.

The carbonaceous material deposited on the conductive substrate having a three-dimensional structure was formed by using the reactor shown in FIG. That is, argon gas is supplied from an argon gas supplier 2 into a bubble container 1 containing benzene which has been dehydrated and then subjected to a distillation and purification operation by vacuum transfer to bubble benzene. And Pyrex glass tube 3
Benzene was fed to the quartz reaction tube 4 via the. At this time, the temperature of the container 1 is kept constant by heating the container 1 by the amount of heat absorbed by the evaporation of benzene.
The amount of benzene was optimized by The reaction tube 4 has a thickness of about 1.
A holder 7 on which a conductive substrate having a three-dimensional structure made of a foamed nickel plate of 5 mm is placed is installed, and a heating furnace 8 is provided around the outer periphery of the reaction tube 4. With this heating furnace 8, the holder 7 and the foamable nickel plate are heated to about 1000 ° C.
Benzene supplied from the Pyrex glass tube 3 was pyrolyzed and the carbonaceous material was deposited on the foamable nickel plate 7 for about 60 minutes. After the thermal decomposition, the gas remaining in the reaction tube 4 was removed through the exhaust equipment 9 and 10.

According to this method, the conductive base material having a three-dimensional structure deposited by this method is filled with a predetermined amount of lithium metal powder having a 140 mesh path, and then roller rolling is performed by a roller rolling machine to obtain a thickness of 0.2 mm. A molded electrode was obtained. FIG. 2 is a perspective view in which the electrode 11 is rolled by the rollers 12, 12. The amount of the charged lithium powder was limited to the amount that the carbonaceous material could absorb, and the lithium metal powder did not remain as an unreacted material after the formation of the electrode, which will be described later.

The thin plate-like electrode body obtained by compression-molding with the lithium metal powder by the roller rolling as described above is immersed in an electrolytic cell containing a propylene carbonate solution containing 1M lithium perchlorate as a solute to obtain a powdery metal. The electrodes were formed by absorbing lithium in the carbonaceous material. The chemically formed electrode was taken out of the electrolytic cell, and after sufficiently removing the electrolyte solution, it was cut into a predetermined shape to obtain an electrode of the present invention.

Incidentally, in the present example, the formation of the electrode was performed, but since the metallic lithium, which is the charge carrier substance, is supported on the carbonaceous material, as described above, the electrode formation treatment is particularly performed before the battery configuration. It does not have to be applied. Thereby, the manufacturing process can be simplified.

The electrode produced by the above method was immersed in a propylene carbonate solution containing 1M lithium perchlorate as a solute and left overnight, and the result was 30 mV to the lithium electrode.
The potential of When the lithium electrode was discharged to 2.5 V, a discharge capacity of 320 mAh was obtained for 1 g of the carbonaceous material. That is, it was found that the electrode of the present invention efficiently absorbed the lithium metal powder. Furthermore, for the purpose of examining the cycle life, for lithium electrodes,
When the charge / discharge cycle of charging to 0 V and discharging to 2.5 V was repeated, the amount of discharged electricity was hardly decreased even after repeating 200 times or more.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view of a carbonaceous material deposition apparatus used for one step in the present invention. FIG. 2 is a perspective view showing a roller rolling process in the present invention.

Claims (1)

[Claims] 1. A carbonaceous material directly deposited on a conductive substrate having a three-dimensional structure by a vapor deposition method by low-temperature pyrolysis of hydrocarbons, and then directly deposited on the conductive substrate. The charge carrier substance capable of reversibly intercalating and deintercalating is filled in the three-dimensional structure, and the three-dimensional structure filled with the charge carrier substance is compressed to form an electrode body. A method for manufacturing a battery electrode, which comprises molding.